Fix a bug where revert auto-correct would revert too much

If there are no uncommitted chars, we shouldn't enter any of
the tests that follow. We didn't use to, but a change today
made it possible - it should not happen.
There is no point in doing the rest of the tests, they are
sure to fail.

Change-Id: I580dd104aff3585de72a93b38989bfd9713f615b